1. Field of the Invention
The invention concerns a shield control device of a longwall shield for carrying out the longwall functions of the longwall shield (longwall unit) in the longwall face working in a mine.
2. Description of Related Art
A control device is known, for example, from DE 103 93 865.6 A1. In the case of this longwall control the individual longwall units, described in this application also as shield or longwall shield, can be controlled from a central control device or by the individual control units that are assigned to each shield (shield control devices) or by an operating device via radio for data transfer. For this purpose each shield control device has a microprocessor with memory to store the code signal (shield codeword) assigned to the shield control device. The data transfer of the external control devices (they are first of all the shield control devices of the other longwall shields of the longwall as well as the central control device) to the function elements of the shield control device via their internal connecting means is effected or carried out only when the shield control device is triggered by the shield codeword assigned to it.
The data transfer within the shield comprises the electrical communication between the shield control device and the function elements (operating magnets and sensors) of the respective longwall shield, in particular therefore first of all the issuing of operational commands to the power source of the longwall shield; these are in particular the operating magnets of the respective hydraulic valves to actuate the power source/actuators as well as in the second place the call/request and the transmission of the measuring signals of those sensors which are assigned to each longwall shield, e.g. to measure the pressure of the power source or measure the inclination or position of the components of the longwall shield. Adjacent or several neighbouring shields can be also triggered from each shield control device to issue commands or to retrieve measuring signals. Basically all signals, i.e. issue of commands (command signals), request of measuring signals (call signals) as well as the measuring signals themselves, in this application: control signals via a common line (busbar) common for all shield control devices, are conveyed to all shield control devices. However, the shield control devices are so programmed, that only that shield control device is addressed and prompted to carry out the control signals, to which the shield codeword issued with the control signal is assigned. All other shield control devices pass on the control signal with the shield codeword.